US4788443A - Apparatus for measuring particles in a fluid - Google Patents

Apparatus for measuring particles in a fluid Download PDF

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Publication number
US4788443A
US4788443A US07/059,734 US5973487A US4788443A US 4788443 A US4788443 A US 4788443A US 5973487 A US5973487 A US 5973487A US 4788443 A US4788443 A US 4788443A
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Prior art keywords
pulses
count
pulse
counter
particles
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US07/059,734
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English (en)
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Yoshiyuki Furuya
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Kowa Co Ltd
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Kowa Co Ltd
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Assigned to KOWA COMPANY LTD., 6-29, NISHIKI 3-CHOME, NAKA-KU, NAGOYA-SHI, AICHI-KEN, 460 JAPAN reassignment KOWA COMPANY LTD., 6-29, NISHIKI 3-CHOME, NAKA-KU, NAGOYA-SHI, AICHI-KEN, 460 JAPAN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: FURUYA, YOSHIYUKI
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/02—Investigating particle size or size distribution
    • G01N15/0205—Investigating particle size or size distribution by optical means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/44—Electric circuits
    • G01J2001/4413—Type
    • G01J2001/442—Single-photon detection or photon counting
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/10—Investigating individual particles
    • G01N15/14—Optical investigation techniques, e.g. flow cytometry
    • G01N15/1456—Optical investigation techniques, e.g. flow cytometry without spatial resolution of the texture or inner structure of the particle, e.g. processing of pulse signals

Definitions

  • This invention relates to an apparatus for measuring particles in a fluid, more particularly to an apparatus for measuring the diameter and concentration of particles in a fluid by the photon counting method.
  • the fluid containing particles to be measured is placed in a measurement cell and irradiated with a laser beam, and the characteristics of the particles are determined from the light scattered by the particles using a photomultiplier.
  • the light scattered by a particle in the fluid becomes weaker in proportion as the diameter of the particle becomes smaller, and it is known that in carrying out detection with respect to weak light, it is more effective to use the photomultiplier in accordance with a photon counting method than to use it in an analogue manner.
  • a laser beam from a laser beam source 1 is condensed on a measurement region 3 by a lens 2.
  • the measurement region 3 is within a measurement cell 4 through which a fluid flows.
  • particles pass through the measurement regions, they scatter the incident laser light.
  • Light scattered by the particle is focused by a lens 5 to form an image at a slit 6, and the light passing through the slit 6 advances to the photocathode of a photomultiplier tube 7 which serves as a photoelectric converter.
  • This light can be considered to be constituted of particles, i.e. photons, and the photons reaching the photocathode cause electrons to be emitted from the same photocathode by the photoelectric effect.
  • the electrons emitted from the photocathode are multiplied in number within the photomultiplier tube 7 by a factor of approximately 10 6 and output as a signal from the photomultiplier tube.
  • This output signal is amplified by a preamplifier 8 and then passed through a peak discriminator 9 which serves as a pulse generator.
  • the threshold value of the peak discriminator 9 is set at the lower limit of the voltage or current value corresponding to the signal at the time when a single electron is emitted from the photocathode of the photomultiplier 7.
  • the peak discriminator 9 outputs a pulse. This pulse is sent to a pulse shaper 10 where it is shaped.
  • the shaped pulses output by the pulse shaper 10 are called “photoelectron pulses” and the method involving the counting of these photoelectron pulses is the “photon counting method.”
  • the photon counting method the number of photoelectron pulses per unit time is proportional to the intensity of the scattered light from the particle. Therefore, by counting the number of photoelectron pulses per fixed time interval, it becomes possible to measure the intensity of the scattered light from particle.
  • the photoelectron pulses output from the pulse shaper 10 are counted in a pulse counter 11.
  • the pulse counter 11 is initialized by a reset signal output from a processor system.
  • the count value of the pulse counter 11 is latched by a latch circuit 12 from which it is read by a processor 13.
  • the latch circuit 12 is controlled by a read signal from the processor 13.
  • this conventional apparatus consists of a single pulse counter 11, a latch circuit 12 for latching the count value of the pulse counter 11, and a processor 13 for reading the count latched in the latch circuit and for controlling the pulse counter and latch circuit.
  • this arrangement results in photoelectron pulses 15 being applied to a terminal 14 of the pulse counter 11 independently of and without relation to the read and reset signals output by the processor 13.
  • a read signal 16 is issued to cause the count value of the pulse counter 11 to be latched by the latch circuit 12.
  • the pulse counter 11 is initialized by a reset signal 17.
  • the pulse width T of the reset signal has to be made longer than the time constant determined by a resistor R and a capacitor C which are provided to prevent malfunction of the pulse counter 11 because of noise.
  • the pulse counter 11 resumes the counting state and the counting of the photoelectron pulses resumes.
  • the count value latched by the latch circuit 12 is read during the period that the read signal from the processor 13 is at high level. By repeating these operations, it is possible to count the number of photoelectron pulses within fixed time intervals.
  • the processor 13 cannot read the photoelectron pulses 15 input to the pulse counter 11 during the time L indicated in FIG. 5B. This means that there is a blind period during which the photoelectron pulses are not counted, so that there arises an error in the measurement of the concentration of the particles in the fluid.
  • An object of the invention is to provide an apparatus for measuring particles in a fluid which has no blind period and is able to count the photoelectron pulses with high accuracy.
  • an apparatus for measuring particles in a fluid by irradiating the fluid containing the particles with a laser beam and analyzing the laser light scattered by the particle to determine the diameter and/or concentration of the particles comprising a laser beam source for producing a laser beam, an optical system for irradiating the fluid containing the particles with the laser light and focusing laser light scattered by the particle, a photoelectric converter for receiving laser light scattered by said particle and converting the same into an electrical signal, a pulse generator for generating pulses in response to said electrical signal, the number of pulses corresponding to the diameter of particles, first and second pulse counters for counting the pulses from the pulse generator, and a processor for processing the pulse count from the first and second pulse counters to derive therefrom the diameter and/or concentration of said particles, the first and second pulse counters being alternately operated for pulse counting.
  • the first and second counters are operated alternately such that one counts pulses while the other is inhibited from counting pulses, the count of each counter being read into the processor while it is inhibited from counting pulses.
  • the arrangement has two pulse counters for counting the pulses and when one of the pulse counters is counting photoelectron pulses, the other is in a non-counting state during which the processing system reads its count value.
  • FIG. 1 is a block diagram schematically illustrating the structure of the apparatus according to the present invention
  • FIG. 2 is a detailed block diagram of the same
  • FIG. 3 is a signal wavefrom diagram for explaining the operation of the apparatus illustrated in FIGS. 1 and 2;
  • FIG. 4 is a block diagram of a prior art apparatus.
  • FIGS. 5A and 5B are a detailed block diagram and a signal waveform diagram for explaining the structure and operation of the prior art apparatus of FIG. 4.
  • FIG. 1 The structure of the apparatus according to the invention is shown in FIG. 1. Components thereof that are identical with those in FIG. 4 are denoted by like reference numerals and will not be explained again here.
  • the apparatus according to the invention is the same as that illustrated in FIG. 4 up to and including the step in which the photoelectron pulses are obtained. It differs in that it has two pulse counters 20, 21.
  • the pulse counters 20, 21 are constituted as 8-bit counters which alternate once every fixed time period in counting the photoelectron pulses input through the terminal 14.
  • the selection between the pulse counter 20 and the pulse counter 21 is carried out by count 1 and count 2 control signals sent by the processor 13 to the pulse counters 20 and 21.
  • the pulse counters 20 and 21 are never simultaneously in the counting state.
  • the selection as to which count value is to be read by the processor 13, that of the pulse counter 20 or that of the pulse counter 21, is carried out by select 1 and select 2 control signals sent by the processor 13 to the pulse counters 20 and 21.
  • the processor 13 reads the count value from the selected pulse counter via a data bus.
  • the 8-bit counter 20 is selected for counting the photoelectron pulses, and when it causes the count 2 control signal to assume high level, the 8-bit counter 21 is selected for counting the photoelectron pulses.
  • the count 1 and count 2 control signals never become high level at the same time.
  • the processor 13 For reading the count value of the 8-bit counter 20, the processor 13 first stops the photoelectron pulse counting operation of the 8-bit counter 20 by switching the count 1 control signal to low level and then prepares the 8-bit counter 20 for reading of its count value by switching the select 1 control signal to high level, whereafter it reads the count value. Similarly, for reading the count value of the 8-bit counter 21, the processor 13 first stops the photoelectron pulse counting operation of the 8-bit counter 21 by switching the count 2 control signal to low level and then prepares the 8-bit counter 21 for reading of its count value by switching the select 2 control signal to high level, whereafter it reads the count value.
  • the select 1 and 2 control signals are never made high level simultaneously.
  • the processor 13 initializes the 8-bit counter 20 by switching the reset 1 control signal to high level, and initializes the 8-bit counter 21 by switching the reset 2 control signal to high level.
  • the high-level pulse widths of reset 1 and reset 2 are made longer than the time constant determined by a resistor R and a capacitor C.
  • the resistor R and capacitor C are provided to prevent noise-induced malfunction of the 8-bit counters 20 and 21.
  • the 8-bit counter 20 will count these photoelectron pulses during the period that the count 1 control signal is at its high level A. During this same period, the 8-bit counter 21 does not count photoelectron pulses. After the lapse of a predetermined fixed period, the count 1 control signal is switched to low level and, simultaneously, the count 2 control signal is switched to its high level B. By this operation the 8-bit counter 20 stops counting photoelectron pulses and the 8-bit counter 21 starts counting them.
  • the processor 13 For reading the count value of the 8-bit counter 20 which has now stopped counting photoelectron pulses, the processor 13 switches the select 1 control signal to its high level C. Following this, while the select 1 control signal remains at high level, the processor 13 reads the count value of the 8-bit counter 20. After completing a read-out of the count value of the 8-bit counter 20, the processor 13 switches the select 1 control signal to low level and switches the reset 1 control signal to its high level F, whereby the 8-bit counter 20 is initialized.
  • the processor 13 switches the count 1 control signal to its high level and, simultaneously, the reset 1 control signal and the count 2 control signal are switched to their low levels.
  • the 8-bit counter 20 starts counting photoelectron pulses and the 8-bit counter 21 stops counting them.
  • the processor 13 For reading the count value of the 8-bit counter 21 which has now stopped counting photoelectron pulses, the processor 13 switches the select 2 control signal to its high level D. Following this, while the select 1 control signal remains at high level, the processor 13 reads the count value of the 8-bit counter 21. After completing a read-out of the count-value of the 8-bit counter 21, the processor 13 switches the select 2 control signal to low level and switches the reset 2 control signal to its high level G, whereby the 8-bit counter 21 is initialized.
  • the foregoing operation is thereafter repeatedly carried out, whereby the counting of the photoelectron pulses by the photon counting method is repeatedly carried out for fixed time intervals.

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  • Chemical & Material Sciences (AREA)
  • Biochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
US07/059,734 1986-06-06 1987-06-08 Apparatus for measuring particles in a fluid Expired - Lifetime US4788443A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP61-130061 1986-06-06
JP61130061A JPH063413B2 (ja) 1986-06-06 1986-06-06 流体中の粒子計測装置

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US4788443A true US4788443A (en) 1988-11-29

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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0383460A2 (en) * 1989-02-13 1990-08-22 Kowa Company Ltd. Apparatus for measuring particles in liquid
EP0391256A2 (de) * 1989-04-07 1990-10-10 GRIMM LABORTECHNIK GMbH & Co. KG Vorrichtung und Verfahren zum Bestimmen der Korngrössenverteilung und der Gesamtkonzentration von Partikeln in einem Gas, insbesondere in Luft
US5133602A (en) * 1991-04-08 1992-07-28 International Business Machines Corporation Particle path determination system
EP0515100A1 (en) * 1991-05-14 1992-11-25 Toa Medical Electronics Co., Ltd. Apparatus for analyzing cells in urine
US5172004A (en) * 1990-05-08 1992-12-15 Kowa Company Ltd. Method and apparatus for measuring particles in a fluid
EP0836090A1 (en) * 1996-10-12 1998-04-15 Evotec BioSystems GmbH Method of analysis of samples by determination of the distribution of specific brightnesses of particles
US20050090886A1 (en) * 2001-02-20 2005-04-28 Biophan Technologies, Inc. Medical device with an electrically conductive anti-antenna geometrical shaped member
US20080004815A1 (en) * 2005-02-25 2008-01-03 Rion Co., Ltd. Particle counter
US20130016358A1 (en) * 2010-03-23 2013-01-17 Ophir-Spiricon Llc Beam scattering laser monitor
US20130218519A1 (en) * 2012-02-16 2013-08-22 Horiba, Ltd. Particle analytical device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08126802A (ja) * 1994-10-31 1996-05-21 Nissin Electric Co Ltd 凝集剤注入制御方式

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4035080A (en) * 1974-08-31 1977-07-12 Nippon Kogaku K.K. Apparatus of spectroscopy of scattering light
US4521521A (en) * 1983-03-11 1985-06-04 E. I. Du Pont De Nemours And Company Particle reagent size distribution measurements for immunoassay
US4676641A (en) * 1986-01-08 1987-06-30 Coulter Electronics Of New England, Inc. System for measuring the size distribution of particles dispersed in a fluid

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4035080A (en) * 1974-08-31 1977-07-12 Nippon Kogaku K.K. Apparatus of spectroscopy of scattering light
US4521521A (en) * 1983-03-11 1985-06-04 E. I. Du Pont De Nemours And Company Particle reagent size distribution measurements for immunoassay
US4676641A (en) * 1986-01-08 1987-06-30 Coulter Electronics Of New England, Inc. System for measuring the size distribution of particles dispersed in a fluid

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0383460A2 (en) * 1989-02-13 1990-08-22 Kowa Company Ltd. Apparatus for measuring particles in liquid
EP0383460A3 (en) * 1989-02-13 1991-08-28 Kowa Company Ltd. Apparatus for measuring particles in liquid
EP0391256A2 (de) * 1989-04-07 1990-10-10 GRIMM LABORTECHNIK GMbH & Co. KG Vorrichtung und Verfahren zum Bestimmen der Korngrössenverteilung und der Gesamtkonzentration von Partikeln in einem Gas, insbesondere in Luft
EP0391256A3 (en) * 1989-04-07 1990-11-28 Grimm Labortechnik Gmbh & Co. Kg Device and method for ascertaining the particle size distribution and particle total concentration in a gas, especially in air
US5172004A (en) * 1990-05-08 1992-12-15 Kowa Company Ltd. Method and apparatus for measuring particles in a fluid
US5133602A (en) * 1991-04-08 1992-07-28 International Business Machines Corporation Particle path determination system
EP0515100A1 (en) * 1991-05-14 1992-11-25 Toa Medical Electronics Co., Ltd. Apparatus for analyzing cells in urine
US5684584A (en) * 1991-05-14 1997-11-04 Toa Medical Electronics Co., Ltd. Apparatus for analyzing cells in urine
US8269965B2 (en) 1996-10-12 2012-09-18 Olympus Corporation Method of analysis of samples by determination of a function of specific brightness
WO1998016814A1 (en) * 1996-10-12 1998-04-23 Evotec Biosystems Ag Method of analysis of samples by determination of a function of specific brightness
US7019310B2 (en) 1996-10-12 2006-03-28 Evotec Ag Method of analysis of samples by determination of a function of specific brightness
US20070020645A1 (en) * 1996-10-12 2007-01-25 Evotec Ag. Method of analysis of samples by determination of a function of specific brightness
US20100230612A1 (en) * 1996-10-12 2010-09-16 Olympus Corporation Method of analysis of samples by determination of a function of specific brightness
EP0836090A1 (en) * 1996-10-12 1998-04-15 Evotec BioSystems GmbH Method of analysis of samples by determination of the distribution of specific brightnesses of particles
US20050090886A1 (en) * 2001-02-20 2005-04-28 Biophan Technologies, Inc. Medical device with an electrically conductive anti-antenna geometrical shaped member
US20080004815A1 (en) * 2005-02-25 2008-01-03 Rion Co., Ltd. Particle counter
US20130016358A1 (en) * 2010-03-23 2013-01-17 Ophir-Spiricon Llc Beam scattering laser monitor
US8988673B2 (en) * 2010-03-23 2015-03-24 Ophir-Spiricon, Llc Beam scattering laser monitor
US20130218519A1 (en) * 2012-02-16 2013-08-22 Horiba, Ltd. Particle analytical device
US9243892B2 (en) * 2012-02-16 2016-01-26 Horiba, Ltd. Particle analytical device

Also Published As

Publication number Publication date
JPH063413B2 (ja) 1994-01-12
JPS62287130A (ja) 1987-12-14

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